U0199 — Lost Communication with Door Control Module “A” (platform variants: Driver Door / Door Module A; some platforms group seat modules separately)

What it means

U0199 is a generic network DTC (second digit 0) that indicates one or more controllers stopped receiving required messages from a door control module—commonly the Driver Door Module (DDM) or “Door Control Module A.” On many vehicles this node rides a body network (e.g., Ford MS-CAN ~125 kbps two-wire, or GM Low-Speed GMLAN ~33.3 kbps single-wire per SAE J2411) and exchanges data with the BCM/gateway, IPC/cluster, radio, keyless/RFA, seat/mirror modules, etc. Some OEM documentation calls out U0199 = Lost communication with DDM, with U0200+ used for other doors/seats (e.g., U0200 Passenger Door Module “B”, U0208 Seat Module “A”). Always check the platform’s DTC chart to confirm which physical module “A” refers to. OBD-Codes.com+2NHTSA+2

Typical symptoms

  • Inoperative or intermittent power locks/windows/mirrors on the driver door
  • Keyless entry/lock requests ignored or erratic; door-ajar/ajar lamp anomalies
  • Cluster or radio messages related to doors; multiple U-codes stored by BCM/IPC/radio while the door module is offline on the topology map
  • On some Chrysler/Jeep/Dodge platforms: front locks/windows inoperative with U0199 (DDM) and/or U0200 (PDM) stored. NHTSA

Why it sets (representative OEM logic)

  • Message timeout from DDM/Door Module A. A supervising node (often BCM, IPC, radio/FDIM) sets U0199 when the expected door-module messages don’t arrive within a calibrated timer (lost comms rather than a logic fault inside the module). OBD-Codes.com
  • Enable criteria (example, Dodge/Chrysler): Monitored continuously with ignition ON and battery 10–16 V; if the network is healthy but no valid data is received from the DDM, U0199 sets. Charm
  • Network layer involved: Most door modules communicate on body CAN. For Ford MS-CAN and other two-wire low/med-speed CAN, the circuit behaves like HS-CAN regarding resistance checks; for GM Low-Speed GMLAN (single-wire J2411) the physical-layer checks differ (see diagnostics). When the gateway bridges body CAN to HS-CAN (~500 kbps), faults on either segment can cause U0199 in peers. centerlearning.com

Common root causes

  1. Power/ground loss at the door module (blown fuse, poor door/body ground, low system voltage)
  2. Wiring faults in the door-jamb flex/boot or kick-panel area (open, short to B+/ground, water intrusion, pin tension/corrosion)
  3. Body-network issues (incorrect termination/bias on MS-CAN; splice-pack/star-point faults on Low-Speed GMLAN)
  4. Connector damage at DDM/PDM (broken/bent pins, water in the door)
  5. Internal door-module/transceiver failure intermittently going error-passive/bus-off
  6. Aftermarket accessories (alarms/remote starts/trackers/audio) spliced into body/HS networks causing noise/backfeed. NHTSA+1

Professional diagnostics (step-by-step)

Network overview & scan strategy

  • Perform a global DTC scan and review the topology/gateway map. Note which nodes report U0199 and whether the DDM (Door A) is offline. If multiple door/seat modules are offline (e.g., U0200/U0208 alongside U0199), suspect a shared body-net or power/ground issue rather than a single module. RepairPal.com

Power/ground checks at the target door module

  • At the DDM connector, verify B+, IGN feed, and ground under load (target ground drop ≤100–200 mV). Many U0199 cases are simply a lost feed or poor ground at the door controller. NHTSA

Bus integrity — match the physical layer

  • Two-wire body CAN (e.g., Ford MS-CAN): Key-off, measure across CAN-H/CAN-L at an appropriate access point—expect ≈60 Ω (two 120-Ω terminators in parallel). Key-on at rest, expect ~2.5 V common-mode with small opposite deviations on H/L; a stuck line or no differential swing indicates a hard fault. NHTSA
  • GM Low-Speed GMLAN (single-wire, ~33.3 kbps, J2411): Do not expect a “60-ohm pair.” Use OEM checks for bias/load and isolate at splice packs/star points; look for clean 0–5 V signaling and for a node pulling the line. (GM service bulletins stress network isolation before parts.) centerlearning.com+1
  • HS-CAN involvement: If your platform’s door module is bridged through a gateway and HS-CAN health is suspect, confirm ≈60 Ω ±5 Ω across DLC pins 6 & 14 and use structured isolation per OEM HS-LAN bulletins. NHTSA

Segment isolation

  • Depower/unplug nodes on the affected branch (door module, door harness connector, related splice/junction) or pull fuses one at a time while monitoring when the network stabilizes and the module comes back online. Chrysler’s bulletin for U0199/U0200 gives module-first checks and simple restore steps; GM HS-LAN guidance details splitting the bus and checking termination before replacing modules. NHTSA+1

Connector/terminal & harness inspection (door-side focus)

  • With trim removed, perform pin-drag tests at the DDM and door-jamb connector; inspect the flex boot for broken conductors and the door/kick panel for water/corrosion. Collision/door-shell service commonly leaves damaged splices. (Field cases frequently find broken pins/wires in the door harness.) Pacifica Forums

Aftermarket device audit

  • Temporarily remove/disable alarms, remote starts, trackers, DLC dongles tied to body/HS networks. Re-evaluate network stability after removal; several OEM bulletins attribute U-code clusters to add-ons. NHTSA

Module actions (last step)

  • Only after wiring/termination/power are proven good: apply any software updates, then replace/initialize the DDM (or other implicated node) per OEM procedures. Chrysler’s bulletin directs DDM/PDM replacement & window calibration only after communication is re-established and verified. NHTSA

Verified fixes

  • Restore door-module power/grounds (replace fuses, clean ground eyelets, correct low system voltage)
  • Repair chafed/open/shorted door-jamb wiring; repin or replace damaged connectors/pins; address water intrusion
  • Correct body-network faults: for MS-CAN, restore proper ≈60 Ω termination; for single-wire GMLAN, fix splice-pack/bias issues and isolate noisy nodes
  • Remove/rewire interfering aftermarket devices affecting body/HS networks
  • Update software when applicable; replace/initialize the DDM (or relevant module) only after network integrity is confirmed
  • Clear codes, perform a drive/operate cycle (lock/window operation), and re-scan to confirm. NHTSA+1

Sources

  • OBD-Codes – U0199: Lost Communication with Door Control Module “A” (generic definition, network context). OBD-Codes.com
  • Chrysler TSB 08-061-12 — Drivers and/or Passenger Front Power Locks/Windows Inoperative; U0199 (DDM) / U0200 (PDM) — inspection and replacement procedure. NHTSA
  • Dodge/Chrysler OEM DTC chart (charm.li mirror) — U0199 monitored with IGN ON; 10–16 V enable; continuous monitoring. Charm
  • GM – Diagnostic Tips: Diagnosing High-Speed LAN Concerns (PI) — backbone ≈60 Ω spec, structured isolation, Data Bus Diagnostic Tool usage (methodology applies when HS-CAN/gateway is implicated). NHTSA
  • RepairPal — U0199: Lost Communication with Door Control Module A (plain-language summary; module mapping list also shows U0200+ seat/door variants). RepairPal.com
  • Practitioner corroboration: forum field cases showing broken door-harness pins/wires resolving U0199 (useful pattern recognition; not primary authority). Pacifica Forums